Three-quarters of Brits will swear loyalty to a company - after being given a free gift

A poll of 2,000 adults found 79 per cent who have picked up some kind of giveaway will tell people about it, with friends (72 per cent), partners (62 per cent) and parents (41 per cent) first on the list to be boasted to.

And the 'thrill' of picking up a treat on the house lasts for the whole day, according to 19 per cent.

Expert psychologists James Cornish and Greg Tucker have revealed the neurological tricks that make Brits’ eyes light up at the thought of getting something free.

The behavioural experts worked with M&S to create a video showing cafe customers reacting with joy after being given a free hot drink – by none other than Matt Willis.

This comes as its cafés offer a free coffee for every six bought, as part of its loyalty scheme.

Matt Willis becomes an M&S Coffee Boy for a day | Simon Jacobs/PinPep

Brits’ eyes light up at the thought of getting something free

James said: "The human brain is brilliantly clever. It has had millions of years of absorbing and processing sensory stimuli, which when subconsciously decoded, provide us with a strong perceptive ability.

“The word ‘free’ triggers an immediate neurological response, activating key areas of the brain related to reward, trust and decision making.

“When a consumer receives something for free, the brain’s reward system is activated releasing dopamine.

“What follows is a sense of pleasure and increases the likelihood that they will enjoy the experience while the release of oxytocin, a hormone linked to trust and bonding, can strengthen a consumer’s affinity with a brand or experience.”

Simon Jacobs/PinPep

Half of Brits have turned into long-term customers - by getting something for free

The study went on to find 54 per cent have visited a business on multiple occasions, purely because they knew there were giveaways afoot.

And what makes a free treat feel more ‘worth it’, according to consumers, is if it’s something they actually like or need (63 per cent).

Nearly as many (59 per cent) enjoy getting something for nothing as a surprise, and 37 per cent put value on the item’s cash value.

More than half (53 per cent), however, admit they have spent more money than they had planned with a business, after having a free item dangled in front of them, with 11 per cent of these shelling out up to £100, or even more, according to the OnePoll.com figures.

As many as half of respondents have even been turned into a long-term customer by getting something free the first time they used a business.

A spokesperson for M&S added: “Getting something for free isn’t just about the financial saving – it’s about feeling special.

“A free gift, no matter how small, brings a moment of happiness and a sense of being rewarded.

“That’s why we regularly offer a coffee on the house to all our customers who are part of the Sparks loyalty scheme.“In a time where people are more mindful of their spending, these little gestures go a long way, which is why getting something for nothing continues to be so popular across all kinds of industries.”